DLA is Nonsense! It should be deleted from the reviews.

Everybody knows small aperture means strong diffraction, but there is no limit from the pixel size and density.


According toDigital SLR Camera Reviews here, so-called DLA (Diffraction Limited Aperture) is the aperture where diffraction begins to visibly affect image sharpness at the pixel level. It says as sensor pixel density increases, the narrowest aperture we can use to get perfectly pixel sharp images gets wider.


This theory assumes the image is a perfect dot and nothing else, and compares its airy disk with pixel size. If the airy disk is larger then pixel size, then the diffraction is visible.
<p class="last"]But actually, the photo image is not a dot, but a continuous surface. When diffraction occurs, the whole the image, every part, every dot gets some kind of blur. So each pixel is definitely affected by some degree of diffraction. There&rsquo;s no such thing called perfectly pixel sharp images. Diffraction could be visible at any aperture, any pixel size theoretically. The size of pixel doesn&rsquo;t limit anything. Digital sensor and film have no difference here.

Hello, Poop...this is Fan.


Fan...this is Poop.





I'm ducking!

Are you advocating that we all use pinhole cameras with f/800 lenses? [:P]

This has been discussed at length here before. Here is some light reading on the subject.


LOL


Mark

I think what DLA needs is a little more understanding and kindness, not agression and hate.

Read the 1st sentence and understand it.

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Originally Posted by Jon Ruyle

I think what DLA needs is a little more understanding and kindness, not agression and hate.






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I do not see it, aggression and hate that is.

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Originally Posted by pin008

Read the 1st sentence and understand it.
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pin008 - We're generally a very friendly and helpful forum community here, and if there's a misunderstanding about anything (or disagreement), those who know generally try to help and weigh in. However, your first post seems a bit aggressive and your second post a bit sarcastic. If you'd like to have a meaningful discussion about DLA, I'm sure those that understand it best will be glad to explain its generally accepted significance in greater detail (or else link to information that has already been covered, as above).


Try to keep an open mind, and if you still disagree with something, explain your position in a respectful manner.

If you think I have some aggressive or sarcastic attitude, I hereby formly apologize! i didnt mean it.


as a non-native speeker, to express my debate is already hard. I can hardly arrange noble words.


Pleasefollow my debates, ignore my words and expressioins.





[:P]

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Originally Posted by clemmb

Quote:

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Originally Posted by Jon Ruyle

I think what DLA needs is a little more understanding and kindness, not aggression and hate.
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I do not see it, aggression and hate that is.

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Well, if someone said you were nonsense and suggested *you* be deleted, wouldn't you feel someone was acting agressively toward you? Might you even feel that someone hated you? Poor, misunderstood DLA. What did it ever do to deserve this kind of treatment?


(I might add that I was, and still am, being a little silly. I don't actually think the OP was being hateful.)


Though, on a (slightly) more serious note, I personally find DLA useful and would not like to see it purged, deleted, stricken from reviews, or otherwise persecuted, oppressed, or marginalized. Sure, opening up wider than the DLA doesn't mean diffraction is impossible to detect. Does that mean it is nonsense? if I stop down way past the DLA, I figure diffraction will have an effect on sharpness. When I do astrophotography, I feel there is little point using a barlow if the f/ number of my scope is greater than the DLA of my ccd.


It's a rule of thumb. Do what you will with it (even if that's nothing).